EXOGENS. 149 



cells 1- rarely 2-seeded. Pedicels drooping in fr. 29 gen., 91 spec. ; 

 1 Am. 1. Biinias. Low herbs. Pis. yellow, racemed; silique 4- 

 sided, bony, often muricate ; 2-celled, 4-seeded. 4 spec, Medit. 

 States. B. orienidlis, Emb., Fig. 191, D. 8. Thysanocarpus. 0, 

 low ; fls. white or violet. Silicle orbic. or ovate ; margin often winged. 

 8 spec, N. W. Am. T. elegans, wings of silicle perforated. 8. 

 Clypeola, similar to last, but wing of silicle dentate. Fls. white or 

 yellow. 8 spec, S. Eur., temp. Asia. 4. tsatis. Silicle winged. 

 0, @, %, fls. yellow, panicled. 30 spec, Medit. States, W. Asia. I. 

 tincibria, Dyer's "Woad ; @, l°-4° high ; Ivs. yield a blue dye, used 

 by the ancient Britons for staining their bodies. Emb., Fig. 191, A. 

 " Tribe 4. Silicle dehisc Valves keeled, pouch-like, compressed at 

 right angles to plane of the usually very narrow replura. Cotyledons 

 accumbent, straight. 14 gen., 80 spec, both worlds. 1. Iberis, 

 CANDyTiTJ'T. 2 outer pet. larger; fls. in flat corymbs, white, pink, 

 lilac, often fragrant. Valves of silicle winged at top. 20 spec, 0, Q|.; 

 low ; often ev. Eur., IST. Af., E. Asia. 2. Megacarpaea. Sta. 

 sometimes 10-16. Silicle very large, valves orbic. Fls. purple. Q|. 

 herbs; 3 spec; deserts. Cent. Asia. 3. Cremolobus. Valves of 

 silicle orbic, winged at back; fls. yellow. Herbs, undershrubs. 5 

 spec ; Peru, Chili. Tribe 6. Silicle of Tribe 4 ; but cotyledons usu- 

 ally incumb. 22 gen., 140 spec, both worlds. 1. Lepidium. Sta. 

 6-4-2. Pet. sometimes 0. Silicle scale-shaped, often winged at top. 

 Fls. small, white. 0, Q|. ; 80 spec, both worlds. L. sativum, Gar- 

 den Cress, 0, Eur. L.. ruderdle. Pet. 0. 0. Eur.; wild in TJ. S. 

 L. virginicum, Peppergrass. Sta. usually 2. 0, l°-2° high, TJ. S. 

 3. Capsella. Fls. white. Silicle heart-shaped ; valves boat-like. 6 

 spec, 0, Old World. C. Bursa-pastbris, Shepherd's Ptjrsk (so 

 called from the silicle's likeness to an old form of purse) ; branching, 

 1° high. Silicle, Fig. 200, C. Eur. ; but it has emigrated with its 

 fellow-countrymen to all parts of the world. The remaining Tribes 

 have the silicle or silique dehisc ; valves plane or concave, parallel to 

 plane of replum. 



Tribe 6. Cotyledons incumbent, conduplicate. 12 gen., 120 spec, 

 both worlds. 1. Sinapis. @. Silique linear or oblong, beaked ; 

 sds. yield a fine oil. Fls. yellow. Cosmopolitan. S. arvensis, Char- 

 lock; .silique knotty. Eur. ; wild in TJ. S. S. alba, Mustard ; sds. 

 pale ; S. nigra. Black M. ; sds. black. Eur. Near to, and by Ben- 

 tham and Hooker included in 3. Brdissica. 0, @. Fls. silique and 

 sds. of S. B. campestris, sds. yield Colza oil. Old World ; original 

 of all the varieties of Turnip. B. olerdcea, Wild Cabbage. Sea- 

 cliffs, Eur. ; original of all the varieties of cultivated Cabbage, Caidi- 

 flower, Broccoli, Brussels-sprouts, Kale, Kohl-rabi. Emb., Fig. 191, 

 0. Tribe 7. Cotyledons incumbent. Sds. 2-seriate. 13 gen., 44 

 spec, both worlds. 1. Camfelina, monotypic Silicle pear-shaped, 

 large, oo-seeded. C. saCim, Gold-of-pleasure, 0, 2° high ; fls. yel- 

 low, racemed. Sts. yield a flax-like fibre; sds. a good oil. Bur., W. 

 Asia ; introduced in U. S. 2. Subularia aqudtiea, Awlwort, mono- 

 typic. Silicle globular, or ovoid; fls. small, white; Ivs. subulate. 

 Stemless aquatic ; sds. ripened under water. Shallow water, arctic 

 and cold regions, Asia, Eur,, N. E. Am. 3. Tetrapoma barbarcefblia, 

 monotypic. Silicle 4-valved ; placentas 4 ; sds. 4-seriate ; replums in- 

 complete ; fls. yellow. @. Siberia ; introduced, TJ. S. Tribe 8. 



